The United States and Russia have discussed the need to develop specific proposals on Iran's nuclear program amid ongoing international talks about fears the country is developing atomic weapons.

Russian Foreign Minister Sergei Lavrov said Monday after meeting with U.S. Secretary of State John Kerry (on the sidelines of an economic summit in Indonesia) that Iran likely wants "more clarity" about the way forward.

"Iran probably wants more clarity," Lavrov said. "More specific steps to be spelled out on the road to the result which we all want to achieve. And I think this will be discussed next week in Geneva, a meeting to which Iran agreed. And to which Iran and three plus three are getting ready in a very constructive mood, as our contacts in New York show."

Kerry said the United States is encouraged by Iran's recent outreach efforts, but that actions, and not words, are what will make a difference.

"So what we need are a set of proposals from Iran that fully disclose how they will show the world that their program is peaceful," Kerry said. "And we have made it clear that if there are those indicators, the United States and our allies are absolutely prepared to move in appropriate ways to meet their actions.”

Kerry said Iran has not responded to an offer the P5+1 group made earlier this year, which called for Iran to stop enriching uranium to 20 percent and halt enrichment at one of its nuclear facilities.

Iranian Foreign Minister Javad Zarif said Sunday that offer was no longer valid, and that the P5+1 should come to next week's negotiations with a "new point of view."

Iran says its nuclear program is strictly for peaceful purposes and wants the international community to lift a range of sanctions imposed for its refusal to halt enrichment activity.

The possible threat of a ballistic missile strike from countries like Iran has led the United States to plan a missile shield in Europe. Russia disagrees with the move, saying the system could neutralize its own strategic missile force and leave it vulnerable to the West.

Kerry said Monday it is too early to make determinations about the system as long as the Iranian threat continues. But he said the U.S. and Russia are continuing to talk about the plan and are trying to work out a way that meets the needs of both countries.